Understanding SignalR

To understand the problem that SignalR solves, we need to understand what web development is like without it. The foundation of the web is HTTP, which for more than 30 years has been great for building general-purpose websites and services. However, the web was not designed for specialized scenarios that require a web page to be instantaneously updated with new information as it becomes available.

The history of real-time communication on the web

To understand the benefits of SignalR, it helps to know the history of HTTP and how organizations worked to make it better for real-time communication between clients and servers.

In the early days of the Web in the 1990s, browsers had to make a full-page HTTP GET request to the web server to get fresh information to show to the visitor.

In late 1999, Microsoft released Internet Explorer 5 with a component named XMLHttpRequest that could make asynchronous HTTP calls in the background. This, alongside...